Itachi's little sister
by Dark Moonlight24
Summary: Tsuki is Sasuke's twin sister but what happens when she lives with Itachi instead of Sasuke?
1. Chapter 1

Hey this is my very first story so here goes nothing.

_**Character bio**_

Name: Tsuki Uchiha

Brothers: Itachi- older Sasuke- older twin

Looks: Midnight dark blue hair, pony tail with side bangs.

Cloths: Blue t-shirt with a yellow half shirt over it, and blue ninja pants.

_**Story Start Past**_

Tsuki and Sasuke were out in the training field practicing their shuriken jutsu, they were so into training that they lost track of time.

"Hey Sasuke I think we should head home it;s getting late." said Tsuki sounding a little worried "Yeah I think we should." Sasuke replied. They got done packing up and headed home "race you there." Tsuki said Sasuke replied with a simple nod, but when Tsuki got to the compound she wish she didn't race him there "hey what's..." he got cut off when he turned his head just to she the whole clan laying there dead "let's go check up on mother and father." suggested Tsuki "yeah I think we should." Then they ran to they're house just to find it empty and silent, they ran to their parent's room Tsuki noticed that Sasuke was trembling and hesitating to open the door so she just swung the door open but regretted doing so once she saw what was in the room. The next thing she noticed was Sasuke yelling at Itachi and Itachi throwing a shuriken at him cutting his shoulder that startled Tsuki a little "Itachi what's going on here?" asked little Sasuke. Then Itachi explained everything then showed it to him using the Mangekyou Sharingan but Tsuki was smart and tried to avoid any eye contact with Itachi "foolish little sister if you won't look at me then I have ways of making you look." after that being said Tsuki felt a presence in front her Itachi grabbed her hair and pushed her head back which made her open her eyes and look into his eyes. You all know what happens next I don't need to explain. Woke up in the hospital and blah blah blah blah.

**_Tsuki's POV_**

****Me and Sasuke went to the compound and the entrance was blocked off by crime scene tape but we went in any way, when we got to our house I went to my room while Sasuke went somewhere in the house, when I got in my room I saw a note.

_Dear Tsuki,_

_**I ****wi**sh that you'**ll** forgive me for what I did.  
I left you and Sasuke alive **c**ause I care ab**o**ut you guy.  
There are so**me b**l**ack** cats in the **f**r**o**nt ya**r**d **you** and Sasuke keep them away_. **  
In **_my room are **5 **things **y**ours ar**e **in **a r**ed box the re**s**t are Sasuke's**.**  
**Don't tell Sasuke.**_

__ Love,  
Itachi

When I got done reading the note I kept on reading it over and over until I noticed that some letters were bold I took a piece of paper and a pen and wrote them down it said: **I will come back for you in 5 years. Don't tell Sasuke.** "What does he mean by that?" I thought out loud.


	2. Chapter 2

**_5 years later_****_ Tsuki's POV_**

Hi my name is Tsuki Uchiha I'm 12 years old I graduated a few weeks ago we just returned from a mission in the land of waves my brother Sasuke and my teammate are in the hospital while I was was perfectly unharmed not even a scratch. I was in the forest training until out of nowhere 10 people that were wearing these black cloaks with red clouds on them surrounded me. I pulled out a kunai and got into a battle stance. "Who are you and what do you want?" When I got done asking this guy that looked like a shark asked this person but I couldn't see his face he was the only one wearing a hat so I had no idea what his face looked like. The shark guy turned to him and asked "Is this her Itachi?" I slightly flinched when I herd him say Itachi, "Itachi?" I said but it was more of a whisper but it was loud enough for everyone to hear. "Yeah that's her." he replied, then this guy that was the shortest out of all of them said "So why did you bring all of us here it's just one girl how hard can she be?" and a guy that looked like a plant answered him "Because it's probably going take all of us just to knock her out." When that was over they all charged at me I kicked this puppet guy into a tree and used a wood style jutsu to hold him down the same thing went for this blond guy, the one with the orange mask and this rain ninja that had his face covered I trapped the one with the scythe in a water prison now the only ones left were fish boy, Itachi and these other 2 that seemed like they weren't even going to do anything. "Is that all you got?" I taunted. Itachi then looked at fish boy and they both nodded then Itachi disappeared and fish boy did some hand signs "Water Style: Exploding Water Shock Wave." I couldn't move in time so I got hit and it slammed me against a tree when the water cleared I raised my left hand forming a chidori but I didn't get to finish Itachi grabbed my hand and slammed it against the tree canceling it out and punched me in the stomach making me cough up some blood, then he pulled me away from the tree and my arms behind my back, and Kisame came up to me and held his sword up to my neck and when it was at my neck I started to feel weaker. Then Itachi grabbed my head yanked it up so that I was facing him I had my sharingan activated and when he saw that it was still activated he was surprised "You could keep it active even in this condition for sure you've grown." with that he yanked my head again and this time I looked him in the eye and saw his mangekyou sharingan activate and the next thing I noticed I was back in the past on that day.

**_Itachi's POV_**  
I put her in Tsukuyomi that should keep her out for a while I put her gently on the floor and me and Kisame had to help the others out once that was finished I went over to where Tsuki was and picked her up but then Tobi ran up to me and said "Itachi-sempai can I carry her please?" "Fine but don't drop her." "Yay." then he grabbed her out of my arms. About half way to the base Tobi tripped and threw Tsuki in the air I glared at him "I thought I told you not to drop her!" Tobi was jumping around holding his foot "But I didn't drop her I threw her." now i was worried that she might get something broken but then I saw Deidara jump up and catch her "well that was a close one un." "Ok Tobi all better now you can hand her to me." I glared at Tobi "You are not gonna carry her Tobi considering the accident that just happened." "Awww Tobi's a good boy." then Deidara had to pop in "No Tobi is a bad boy" then Tobi started sulking in the corner.


	3. Chapter 3

**Me: Well hello there peps ^_^  
Pein: Time for another installment of Itachi's little sister -.-**

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~Tsuki~

I slowly opened my eyes and winced a bit at the slight head ache I had. I tried to move my hand to my head but some chains restrained me. 'What the?' I thought as I tugged at the chains. "Give it up." I heard a cold, familiar voice told me, as my head whipped to the side to see Itachi standing there. I let out a low growl as he approached me. "What do you want?" I spat as I tried to move further away from him, but to no avail the chains held me back. "Like I said, give it up. There's no way you can break those chains. Only a beast can break it." He told me, as I just rolled my eyes. 'A beast huh?' I smirked mentally.

I chuckled a bit earning a weird look from Itachi. I closed my eyes and concentrated on my beast. "What now? I'm sleeping." He whined, no literally. My demon is a horse. His name's Akuma No Uma, meaning demon horse. Akuma No Uma was black with fire for a mane and tail, fire at his hooves, a horn about 2 feet long behind each ear, blood red wings, and red eyes that paralyze you in your darkest fears. Rumors say that for every feather on his wings stand for every life he took, not true, they are just like that. "Can you help me break free? Please?" I pleaded in a kind voice. "Fine." He grumbled, as his chakra surrounded me, and he went back to sleep.

I opened my now blood red eyes and tugged at the chains, snapping them. I chuckled at my brother's reaction. "Surprised?" I chuckled, as the others ran in, due to the sound of snapping chains. "What the f*ck! How the f*ck did she get loose!" The silver haired guy shouted, as I stared into his eyes. I second later his eyes widened in fear as he froze and body trembled a bit. "My, my, for someone like you to be scared of something like that. Interesting." I chuckled while the others just looked at me in shock. "D-d-don't l-l-look in-n-to her e-e-eyes." The guy stuttered, making me laugh a bit.

Just as I turned around Itachi punched me in the stomach, making me double over in pain. Then, Kisame placed his sword on top of me! I felt myself get weaker as Uma's chakra faded til my chakra was back and that to faded. I looked around and saw Kisame's foot next to my face, so I opened my mouth, and bit him above his foot, earning a kicked in the face from him. I grunted is pain as his foot connected with my face. I felt some blood seep out from the side of my mouth, as much as I didn't want to do it, it was more of a 2nd nature thing. And so, I liked the blood from the side of my lip.

Once I realized what I did, I shoved everyone out of the room, shut the door, locked it, and slid to the floor clutching my head with my breathing jagged. "Ok, calm down. Don't lose yourself. You can control it." I told myself, as my voice broke, and tears threatened to flow out of my eyes. I started to tremble as the blood got to me.

My head shot up when I heard some squeaking noises. I saw a few rats out of the corner of my eyes, eating some crumbs off the floor. 'Sorry little fellas.' I apologized silently, as I hissed and bit into one, while I held the others by their tails in my other hand. I threw the dead rats on floor once I drank them dried. "Tsuki! You still in there! Open this door!" I heard Itachi yell, while I just rolled my eyes, walked over the door, unlocked it, and sat on the bed. "Well, that was weird. Thought you escaped." Kisame chuckled.

I saw Zetsu, the freaky plant guy, look at the five rats on the floor. "These rats. **They've been sucked dry.**" Zetsu informed the others, as I saw them looked at him in shocked. "Sucked dry of what?" Hidan asked with a voice full of fear. "**Blood.**" The black side answered, as I just kicked one into the wall, breaking it apart as if it were a kid's toy. Everyone looked at me weirdly so I just laid down on the bed. "What? You think I did it? Puh lease, I'm still human." 'Half human anyways' I added silently in my mind.

After some arguments I finally caved and joined the Akatsuki. "Alright, now Itachi will show you around the hideout." Pein told me while everyone left. Just as I walked out the door after Itachi and froze as a strong smell of blood got to me, and I'm pretty sure my eyes have turned a shiny ruby red by now. Yes, my as shine like a ruby, even at night, it would shine like a sparkling ruby in the sunlight. "Where's the nearest door leading to a nearby forest." I demanded, as I covered my face. "Why? Planning on running away?" He said in an emotionless voice. I had to hold myself back from lashing out at him. "Just. Do it." I hissed dangerously, making him sigh, while leading my outside. "I'll be back in five." I told him as I dashed into the forest.

I scurried to the forest, searching for a deer or at least something big-ish. Just to my luck I ran into a grazing deer. I apologized silently as I launched myself at it and bit into it's neck, draining every last drop of blood that I could, satisfying my hunger. For now. I ran back to my big brother once I threw the deer aside. "What are you hiding Tsuki?" Itachi asked my with a bit of suspicion in his voice. "Nothing of importance now." I answered him as we went back inside,

Once he showed me every inch of the hideout we hung out with everyone else in the living area. But by that time I was a bit jittery due to the smell of blood, which is weird somehow. "Hey, what's wrong with you?" Sasori asked in a bored tone but then again he always sounded like that. "It's funny really, there seems to always be a strong smell of blood in this place. And the smell of it just makes me feel sick to my stomach." I lied as I watch him look at me in silence before explaining. "The smell would come from Hidan's room. His religion has to do something about sacrificing living things, well more of kill then sacrifice. He does that at least once everyday." And that is when I flipped. "At least once! Everyday!" I nearly shouted, as everyone looked at me, making feel a bit uncomfortable.

"I need some fresh air." I said through clenched teeth, then I stormed out to the backyard forest. I ran to the lake and collapsed by a nearby boulder and punched the ground, making a dent/hole in the ground.

~Others~

"What does she even do out there, un?" Deidara asked after Tsuki stormed outside. "OH! CAN TOBI GO SEE!" He shouted, making everyone cover their ears. "Yeah sure, and we'll let a pig run the Akatsuki for the damn day while we're f*cking at it!" Hidan said sarcastically, as Zetsu volunteered. "Alright, just tell us everything once you think you have enough info about what she does. But no one tell her about this *cough* Tobi *cough*" Kakuzu told them while Tobi just kept on shouting 'Tobi's a good boy!' over and over.

Zetsu sunk into the ground and appeared near Tsuki, being sure that he was hidden.

~Normal No one~

Tsuki sat there with eyes darting here and there, trying to calm down due to an anxiety attack from her blood lust and missing Sasuke. 'Wow, just what has she been through?' Zetsu asked silently as he watch her. Tsuki watch the fishes swim back and forth, running into other fishes, and yadi yadi yada. "Ugh! I'm starving!" Tsuki groaned out of starvation, as she watched the fish swim. Tsuki licked her lips in a hungry way with a tiny _slurp_ like noise and a tiny pop like noise when her tongue went back in her mouth. "Wonder how fish blood tastes like?" She smirked, while her hand darted at inhuman speed and grasped the fish. Tsuki watched the squirming fish with a twisted expression on her face.

Tsuki gripped the fish harder and bit into it, but just as the first drop of the blood made her want to barf, so she threw the -now dead- fish back into the lake. "Ugh. That's nasty!" She hissed and she spit out every last bit of blood out of her mouth. "Sticking to mammal blood." She noted out loud, as she watch a rabbit hop by. Tsuki snatched the rabbit by it's ear and watched as it tried to kick itself free.

Tsuki sighed as she snapped it's neck, making it's body go limp, indicating that it was dead. She bit into it, draining it of every last single drop of blood it had, not wanting to let it go to waste. She smacked her lips together once she was down and threw the rabbit into some bushes. She sighed in relieved while sitting back down. "Zetsu, I know you're there." She said with closed eyes, as Zetsu appeared out of the ground in front of her. "How did you know it was me and that I was even here?" He asked, making her chuckle. "I can smell you." Was her simple reply.

"What did you see?" She growled, opening one eye, looking at him that one eye. "Well what ever you saw, I don't care. As long as you don't tell anyone. You do, it'll be the last thing you ever do." She threatened, earning a low chuckle from him. "I won't. **Yet that is**." He told her, making her eyes shot open, snarling at him. Tsuki pounced at him but he just sank back into the ground, going back to the others.

Tsuki scurried back to the hideout but kept on tripping. 'No, no, no, don't, no. Nononononononononononono.' She pleaded silently, while swinging the door open, getting jumped on by Hidan, and Kakuzu. "Hey! What's going on! Let me go! I didn't do anything!" She screamed as she struggled to get free from their vice like grip. Kisame held up a kunai to her neck, threatening her to spill.

Tsuki just snarled at him, making him chuckle, then he just knocked her around a bit and she finally spilled. "What do you want to know?" She frown, scolding herself for how she caved. "Everything." Sasori answered for everyone, as she sighed. "I killed those rats in the room, I'm not human but I'm not a vampire, I'm half. I have demon sealed inside of me and I stormed out those two times to go hunt for food, since my brother Sasuke isn't here, since I'm uses to feeding off of him." She told them, earning a 'She's gonna turn us into vampires!' from Tobi who was running around the hideout.

"Psh, like I'd turn you guys, besides, I'm half, so even if I wanted to I couldn't." She scoffed, earning a hey from Hidan and Deidara. "What? It's true." She shrugged. "How did you even get turned yourself, un?" Deidara asked. Tsuki took in a deep breathe before starting to explain.

~Flashback Tsuki's POV (She's remembering this while she's telling them)~

It's been about a year and a half since the clan's murder, Sasuke decided to train while I just wanted to relax for a day, which was probably a bad idea. I was sitting there by a secret lake that I've found when I was running away from some assassins that were after me. My mind began to wonder as I looked at the lake and took my unattached sleeve from my left arm off to look at the seal that kept my demon sealed inside of me. The seal was a ring around my fore arm that was made of feathers, I think there's 25 feathers total, the seal will come undone and the demon will be free once all 25 feathers disappear.

I admittedly pulled the sleeve back on my fore arm as I heard someone's creepy chuckle. "W-w-who's there?" I stuttered, trying to stand up, but I couldn't due tot he fact that I was paralyzed some how! "Nice to finally meet you, Tsuki. My name is Orochimaru." The creepy voice said, freaking me out. "W-w-what do y-y-you want with m-m-me?" I asked with a voice full of fear. A small gasped escaped my lips as he appeared in front of me, only mere inches away from me.

My eyes widened as I saw him pull out a shot needle filled with some kind of orange substance in it, making me whimper due to the strange color of the substance and how that thing would be inside me any second. "You'll find out if you live my dear." He chuckled, as I tried to struggled to move. I flinched, wait flinched? Yes! I'm free. But the needle was inside of me, and the syringe was going inside my system, I kicked him and ran as fast as I could to Sasuke.

When I looked back I saw the needle that was still in his hand and saw half of it empty. 'Great, now what's gonna happen?' I asked myself, as my head started spinning. I started groaning in pain every now and then as my vision blurred, but good thing I found Sasuke. "Ugh...Ummm...Niiiiii-saahhaan..." I groaned in pain as I weakly clung onto his arm but blacked out.

Once I woke up my head hurt, my throat felt as if there was a fire in it. "Ugh...Sasuke? Is that you?" I groaned, as I tried to make out his figure. "Yeah it's me...What happened? You were screaming and thrashing like crazy for the past few days. You really had me worried and you wouldn't wake up." He told me, as I found it hard to hold myself back from pouncing on him, and biting into his neck.

His words started to fade as I slowly lost control of myself and tackled him to the ground. "Ts-Ts-Tsuki! W-w-what are you doing! Get off of me!" He demanded as I licked a vein on his neck, and bit down hard. I heard a small gasp escape from his lips as I bit down, I drank about maybe 3 or 4 cups of his blood, I don't know, I just drank a lot that's all I know.

Once I regain control of myself I pulled away and hid under my blanket. "It's not possible, it can't be." I whimpered, as I felt Sasuke lift the blanket off and hugged me. "No, I'm gonna hurt you again." I cried while trying to push him away, but to no avail. "You won't and tell me what happened?" He asked well more of demanded. I explained everything to him and well, we just went on from there, I drank from him when ever need or I just ran to the woods and caught an animal.

~End Still Tsuki POV~

I took in a shaky breathe as I finished. "There, that's the whole story. Hopefully that will clear things up." I told them, as the zombie duo let me go. I bit my bottom lip as I went to my room.

~Pein~

'Of course, it would be Orochimaru, who else would be cruel enough to mess with someone's system.' I thought, as I overheard the whole conversation in the shadows. I remembered when we found the Sanin back in the day and he just wanted to kill us on the spot, calling us a nuisance along with it. I knocked on her room door, door, i came in after I heard a 'come in' from the other side. "You have a mission with me tomorrow, be ready by 9 am, and make sure you're packed for 2 days." I told her, earning a nod from her as she turned back to what ever she was doing. 'I can tell her on the mission, when we're alone with no one to interrupt.'

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**Me: Well that's it for this CH. Anyone got any ideas for the mission?**

Review please


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